The Pro Staff strap from Nikon distributes a binocular's weight across your back and shoulders, as well as keeping them close to your body to prevent swinging around. It is highly recommended for using binoculars during activities where you'll be moving around quite a bit, though you'd never want to be galloping upon a horse with such a contraption. An added benefit to a suspender harness strap is that you'll be able to hold your binocular steadier thanks to the elasticity maintaining a bit more tension, which lends significant support. Attaches to any binocular though gargantuan monstrosities, such as those with objective lens diameters exceeding 50mm, are not recommended.